Smith JN, Double M and Townsend A (2025). Aerial survey of the Australian southern right whale (Eubalaena australis) ‘western’ population and development of AI for photo-identification. Report to the National Environmental Science Program. Murdoch University.
Overview
Southern right whales (Eubalaena australis; SRWs) were a target of intense commercial whaling during the 19th and 20th century, and as a consequence SRWs in Australia were considered rare to virtually extinct between 1870 to 1960. Initial signs of recovery of the species only occurred in the mid 1970’s in south-west Australia. This technical report provides the results from the aerial survey undertaken between 21-28 August 2024 in coastal waters from Perth (Western Australia) to Ceduna (South Australia) as part of the long-term aerial survey program that has been undertaken annually off the south-west Australian coast since 1976 to monitor recovery of the species, resulting in a long-term dataset spanning 49 years. The aerial surveys involve undertaking population counts and collection of photo-identification (photo-id) data to provide relative abundance estimates and inform population demographic trends and reproductive parameters of SRWs for the ‘western’ population. The data from the aerial surveys directly inform the Australian Government National Recovery Plan for Southern Right Whales, South Australia and Western Australia State Government conservation management plans and is of high interest to the International Whaling Commission Scientific Committee, marine mammal research community and the general public.
From this recent aerial survey, the long-term dataset on the ‘western’ population of SRWs in Australian waters shows a decreasing rate of increase in population size (N = 2,242 whales) across the entire time-series (1993-2024), a non-significant trend in abundance since 2011 for both unaccompanied animals (p = 0.18) and female/calf pairs (p = 0.60), and a negative rate of annual increase for female-calf pairs (-1.31%) indicating a decline in female-calf abundance. There continues to be highly fluctuating annual variation in abundance for both unaccompanied animals and female-calf pairs, with persistent low numbers of unaccompanied animals. The results from this survey suggest the western population of SRWs is no longer recovering at previous historical growth rates, with current abundance well below (~20%) pre-whaling abundance. To improve the processing of SRW photo-id data, Artificial Intelligence (AI) tools have successfully been developed in this project (2023/24) to automate image workflows to process the photo-identification data and improve image processing/matching capabilities. Further development of the AI in 2025 will build on the success of the tools developed, through a more comprehensive training dataset and new AI matching interface to enable visualisation of potential matches.
It is critical the SRW is afforded high levels of protection in biologically important areas (e.g. reproduction BIA) and annual surveys are continued to assess the status of the species through long-term population trend data and inform federal and state conservation management actions and regulatory assessments of marine-based activities (e.g. offshore wind, seismic survey).
